Cordless electrically-powered concrete screed

Abstract

A power unit is configured for use as part of a concrete screed and includes a frame and a powered drive. The frame includes a drive housing. The powered drive is operably supported by the drive housing and is configured to rotate a rotatable concrete forming drum. The powered drive includes an electric motor and a battery operably coupled to the electric motor and configured to power the electric motor. The powered drive includes a drive shaft drivingly connectable relative to the drum, with rotation of the drive shaft causing corresponding rotation of the drum.

The invention claimed is: 
     
       1. A power unit for a concrete screed including a rotatable concrete forming drum, said power unit comprising:
 a frame including a drive housing; and 
 a powered drive being operably supported by the drive housing and configured to rotate the drum, 
 said powered drive including an electric motor and a battery operably coupled to the electric motor and configured to power the electric motor, 
 said powered drive including a drive shaft drivingly connectable relative to the drum, with rotation of the drive shaft causing corresponding rotation of the drum, 
 said drive housing presenting a drive chamber to at least partly receive the powered drive, 
 said drive housing including an access opening communicating with the chamber and permitting battery insertion and removal relative to the chamber, 
 said drive housing including a door shiftable into and out of a closed position in which the door restricts access to the battery. 
 
     
     
       2. A power unit for a concrete screed including a rotatable concrete forming drum, said power unit comprising:
 a frame including a drive housing; and 
 a powered drive being operably supported by the drive housing and configured to rotate the drum, 
 said powered drive including an electric motor and a battery operably coupled to the electric motor and configured to power the electric motor, 
 said powered drive including a drive shaft drivingly connectable relative to the drum, with rotation of the drive shaft causing corresponding rotation of the drum, 
 said frame including a handle to be grasped by a user, with the handle being configured to facilitate manual advancement of the concrete screed in a forward direction, 
 said handle and said drive housing being pivotally attached relative to each other so that the handle is swingable relative to the drive housing about a pivot axis that is transverse to the forward direction, with the handle swinging between an operating position and a transport position, 
 said handle including a grip and a relatively shiftable drive controller operably coupled to the powered drive so that shifting of the drive controller operates the powered drive and thereby drum rotation, wherein the drive controller is shiftable to operate the powered drive when the handle is in the operating position and the drive controller is restricted from operating the powered drive when the handle is in the transport position. 
 
     
     
       3. The power unit as claimed in  claim 2 ,
 said drive controller being prevented from shifting when the handle is in the transport position. 
 
     
     
       4. The power unit as claimed in  claim 3 , further comprising:
 a drive control device extending between the handle and the powered drive and being configured to operate the powered drive, with the frame and drive control device cooperating to prevent shifting of the drive controller when the handle is in the transport position. 
 
     
     
       5. A power unit for a concrete screed including a rotatable concrete forming drum, said power unit comprising:
 a frame including a drive housing; and 
 a powered drive being operably supported by the drive housing and configured to rotate the drum, 
 said powered drive including an electric motor and a battery operably coupled to the electric motor and configured to power the electric motor, 
 said powered drive including a drive shaft drivingly connectable relative to the drum, with rotation of the drive shaft causing corresponding rotation of the drum, 
 said frame including a handle to be grasped by a user, with the handle being configured to facilitate manual advancement of the concrete screed in a forward direction, 
 said handle including a grip and a relatively shiftable drive controller, 
 said powered drive further including a shiftable drive control element operable to control the electric motor and thereby rotation of the drum; and 
 a mechanical control connection extending between the drive controller and the drive control element so that shifting of the drive controller corresponds with shifting of the drive control element. 
 
     
     
       6. The power unit as claimed in  claim 5 ,
 said electric motor comprising a continuous variable-speed drive motor operable to drive the drive shaft through a range of rotational speed, 
 said drive control element and said drive controller each being variably positionable, with the position of the drive controller and thereby the drive control element corresponding to the rotational speed of the drive shaft. 
 
     
     
       7. The power unit as claimed in  claim 6 ,
 said drive controller including a lever pivotal relative to the grip, 
 said mechanical control connection comprising a linkage operably interposed between the lever and the drive control element. 
 
     
     
       8. The power unit as claimed in  claim 5 ,
 said powered drive comprising a right-angle drill, 
 said drill including a transmission drivingly interconnecting the electric motor and drive shaft. 
 
     
     
       9. The power unit as claimed in  claim 5 ,
 said handle and said drive housing being pivotally attached relative to each other so that the handle is swingable relative to the drive housing about a frame pivot axis that is transverse to the forward direction, with the handle swinging between an operating position and a transport position, 
 said mechanical control connection comprising a linkage operably interposed between the drive controller and the drive control element, 
 said linkage including a first link associated with the handle and a second link associated with the drive housing, 
 said first link and said second link being pivotally attached relative to one another so as to be relatively swingable about a linkage pivot axis, with the frame and linkage pivot axes being adjacent one another and parallel so that the linkage permits swinging of the handle. 
 
     
     
       10. The power unit as claimed in  claim 9 ,
 said drive control element being shiftable into and out of an off position in which the drive shaft is not rotating, 
 said first and second links being cooperatively shiftable when the handle is in the operating position to move the drive control element out of the off position, 
 said frame including a stop, 
 at least one of said first and second links engaging the stop when the handle is in the transport position to restrict linkage shifting associated with movement of the drive control element out of the off position. 
 
     
     
       11. The power unit as claimed in  claim 9 ,
 said linkage operably associated with the frame so that the drive controller is shiftable to operate the powered drive when the handle is in the operating position and the drive controller is restricted from operating the powered drive when the frame is in the transport position. 
 
     
     
       12. A power unit for a concrete screed including a rotatable concrete forming drum, said power unit comprising:
 a frame including a drive housing; and 
 a powered drive being operably supported by the drive housing and configured to rotate the drum, 
 said powered drive including an electric motor and a battery operably coupled to the electric motor and configured to power the electric motor, 
 said powered drive including a drive shaft drivingly connectable relative to the drum, with rotation of the drive shaft causing corresponding rotation of the drum, 
 said drive housing presenting opposite proximal and distal housing ends and a housing axis extending between the housing ends, 
 said powered drive being swingably attached relative to the drive housing at a support joint to swing about a transverse axis extending transversely to the housing axis. 
 
     
     
       13. The power unit as claimed in  claim 12 ,
 said frame including a handle to be grasped by a user, with the handle being configured to facilitate manual advancement of the concrete screed in a forward direction. 
 
     
     
       14. The power unit as claimed in  claim 13 ,
 said drive housing presenting opposite proximal and distal housing ends and a housing axis extending between the housing ends, 
 said power unit including a support stand adjustably attached relative to the drive housing and extending transversely relative to the housing axis, with the support stand being configured to engage the ground and in part support the drive housing in an upright orientation. 
 
     
     
       15. The power unit as claimed in  claim 13 ,
 said handle and said drive housing being pivotally attached relative to each other so that the handle is swingable relative to the drive housing about a pivot axis that is transverse to the forward direction, with the handle swinging between an operating position and a transport position. 
 
     
     
       16. The power unit as claimed in  claim 15 ,
 said drive housing presenting opposite proximal and distal housing ends and a housing axis extending between the housing ends, 
 said handle extending proximally from the pivot joint in the operating position and extending distally from the pivot joint in the transport position, with a transport center of gravity being defined when the handle is in the transport position, 
 said handle extending axially on opposite sides of the center of gravity in the transport position when the housing axis is oriented laterally to facilitate manual carrying of the power unit. 
 
     
     
       17. The power unit as claimed in  claim 12 ,
 said frame including a handle to be grasped by a user, with the handle being configured to facilitate manual advancement of the concrete screed in a forward direction, 
 said handle including a grip and a relatively shiftable drive controller operably coupled to the powered drive so that shifting of the drive controller operates the powered drive and thereby drum rotation, 
 said powered drive including a shiftable drive control element operable to control the electric motor and thereby rotation of the drum; and 
 a mechanical control connection extending between the drive controller and the drive control element so that shifting of the drive controller corresponds with shifting of the drive control element, 
 said powered drive being swingable to position the drive control element relative to the mechanical control connection for operable engagement therebetween. 
 
     
     
       18. The power unit as claimed in  claim 17 ,
 said powered drive including a power tool case that operably supports the electric motor, battery, drive shaft, and drive control element within the drive housing, 
 said power tool case swingably attached to the drive housing at the support joint; and 
 a drive adjustment device shiftably attaching the power tool case to the drive housing at a location spaced from the support joint to swingably position the powered drive relative to the drive housing. 
 
     
     
       19. The power unit as claimed in  claim 12 ,
 said frame including a handle to be grasped by a user, with the handle being configured to facilitate manual advancement of the concrete screed in a forward direction, 
 said handle and said drive housing being pivotally attached relative to each other so that the handle is swingable relative to the drive housing about a pivot axis that is transverse to the forward direction, 
 said powered drive being operably supported by the drive housing and including a rotatable drive shaft; and 
 a drive coupler attached to the drive shaft and removably attachable to a connection shaft of the drum so that rotation of the drive shaft is imparted to the connection shaft, 
 said drive coupler configured to align the drive and connection shafts on a common rotation axis without permitting off-axis swinging of the shafts relative to one another, such that swinging of the drive housing relative to the drum is at least substantially restricted.